1. Field of the Invention
The present invention relates to bicycles and more particularly, to tandem trailers and more particularly, to a retractable frame structure for tandem trailer that allows adjustment of the bottom frame thereof between an extended position for two-seat seating arrangement in a fore-to-aft manner and a retracted position for one-seat seating arrangement.
2. Description of the Related Art
A conventional trailer, for example, U.S. Pat. No. 6,959,938B1, is known comprising: a bottom frame, two wheel holder frames respectively affixed to said side bars to support a respective wheel, a trailer bar pivotally connected to one front lateral side of the bottom frame and linked to a bicycle, and a seat for the sitting of a young child. When a young child is sitting on the seat, the bicycle can be propelled to drag the trailer. According to this conventional design, the space defined in the frame structure of the trailer is not adjustable, and therefore only one single seat is provided for one child to sit thereon.
Further, U.S. Pat. No. 7,341,265A, issued to the same inventor of the aforesaid prior at trailer, discloses a frame structure for foldable baby trailer. According to this design, the bottom frame of the frame structure for foldable baby trailer is transversely retractable between an extended position for operation and a received position to save space occupation conveniently for storage and delivery.